相关实验视频

Updated: Sep 14, 2025

Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function

Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function

Published on: June 21, 2017

卡纳瓦宁tRNA编辑脱乙酶CtdA的产业驱动进化

Nino Tabagari¹, Franziskus Hauth^2,3, Jennifer R Fleming¹

¹Department of Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.

Journal of structural biology: X

|July 21, 2025

概括

卡纳瓦尼尔-tRNA脱乙酶 (CtdA) 通过从tRNA中去除非蛋白质原氨基酸canavanine来防止有毒蛋白质的结合. 结构和突变性研究揭示了CtdA的活性部位及其与其他编辑酶的关系.

科学领域:

生物化学生物化学
分子生物学分子生物学
结构生物学结构生物学

背景情况:

蛋白质由20种标准氨基酸构成,但可以加入非标准的氨基酸,导致毒性.
卡纳瓦宁是一种L-氨酸模拟物,当氨酸-tRNA合成酶错误地加载tRNA时,它被错误地纳入细菌蛋白.
卡纳瓦尼尔-tRNA脱乙酸酶 (CtdA) 是第一个被发现的酶,可以从错误充电的tRNA中去除非蛋白质原性氨基酸,防止蛋白质损伤.

研究的目的:

为了阐明CtdA的晶体结构.
通过位点定向突变发生的方法来研究CtdA活性部位.
了解CtdA和其他tRNA编辑酶之间的进化关系.

主要方法:

进行X射线晶体学以确定CtdA结构.
位点定向突变发生,以探测活性位点残留物.
与相关酶的序列和结构比较.

主要成果:

CtdA是一种单体酶,具有用于canavanine结合的中心腔和用于tRNA相互作用的充电表面.
CtdA与Phenylalanine-tRNA-Synthetase (PheRS) 的B3/B4编辑域共享了一个保存的3D折叠.
在CtdA中的特定残留物 (Y104,N105,E118,E191) 对催化非常重要,N105被保存并可能参与协调催化水.

结论:

CtdA有效地编辑错误的tRNA,防止细菌中的canavanine毒性.
对CtdA的结构和机制洞察力扩大了我们对tRNA质量控制机制的理解.
CtdA代表了保留折叠中的一个独特的子类,为tRNA编辑酶的演化和功能提供了一个模型.

关键词:

印尔介导的折叠进化过程局部导向的突变发生.在X射线晶体学.编辑tRNA的方法

更多相关视频

A Nonsequencing Approach for the Rapid Detection of RNA Editing

A Nonsequencing Approach for the Rapid Detection of RNA Editing

Published on: April 21, 2022

CD Spectroscopy to Study DNA-Protein Interactions

CD Spectroscopy to Study DNA-Protein Interactions

Published on: February 10, 2022

相关概念视频

RNA Editing

RNA Editing

RNA editing is a post-transcriptional modification where a precursor mRNA (pre-mRNA) nucleotide sequence is changed by base insertion, deletion, or modification. The extent of RNA editing varies from a few hundred bases, in mitochondrial DNA of trypanosomes, to a just single base, in nuclear genes of mammals. Even a single base change in the pre-mRNA can convert a codon for one amino acid into the codon for another amino acid or a stop codon. This type of re-coding can significantly affect the...

Allosteric Proteins-ATCase

Allosteric Proteins-ATCase

Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...

Transfer RNA Synthesis

Transfer RNA Synthesis

One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...

Gene Evolution - Fast or Slow?

Gene Evolution - Fast or Slow?

The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...

Exon Recombination

Exon Recombination

The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon...

tRNA Activation

tRNA Activation

Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...